1. Technical Field
The present invention relates to a communication apparatus and a communication method.
2. Related Art
In recent years, the technique of establishing a new service by combining various services distributed over a network such as the Internet has been attracting attention. Particularly, a method called “Web service” has started spreading widely. A Web service is formed on the basis of known standard techniques such as HTTP (Hyper Text Transfer Protocol), SOAP (Simple Object Access Protocol), and XML (Extensible Markup Language).
In a business organization, a system called “firewall” is normally employed on the boundary between the Internet and the internal network of the company, so as to limit accesses to the internal network from the Internet. In such an environment where the firewall exits, there are needs to call for services involving a computing resource existing in the internal network through services formed on the Internet.
To satisfy such needs, it is necessary to enable communications from the Internet to internal networks. To do so, the VPN (Virtual Private Network) technique or a technique called “Reverse Proxy” is normally used. The VPN technique has the problem of requiring an expensive device such as a special-purpose router. According to the Reverse Proxy technique, a proxy that has an orientation opposite to the regular orientation is provided on a network boundary, and internal network resources are disclosed in a limited fashion. However, Reverse Proxy has the problem of requiring a change in the structure of the firewall or the network boundary.